Category Archive 'Devonian Period'

29 Jul 2018

Glimpses of a Mass Extinction in Western New York

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Fossil tree stump, Gilboa, New York.

First, they came for the brachiopods…

In the New Yorker, Peter Brannan finds in Western New York State abundant evidence of Global Warming and planet-wide mass extinction having nothing whatsoever to do with human industrial production or the automobile.

[T]he Hudson Valley roughly marked land’s end, and, by now, I had pushed off this secret coastline to head west, and offshore. The red earth that earlier bracketed the highway—rumors of ancient rivers on land—now gave way to gray, banded rocks filled with seashells, where stacks of seafloor piled up, millennia-thick.

“The farther west you go in New York, it’s all marine fossils,” a paleontologist told me before I left. “New York would have been facing into a great continental sea. All the way out to Ohio, it’s all marine.”

This upstate ocean poked out from under farmland, and crumbled from rock walls behind gas stations. In the Devonian period—hundreds of millions of years ago—it was filled with sea lilies, sea scorpions, armor-plated monster fish, forests of glass sponges, and patch reefs of strange corals. At night, these reefs were cast in shimmering chiaroscuro, inviting moonlit patrols of sharks and coelacanths. Where the water met land in eastern New York, dawn revealed fish hauling ashore on nervous day trips—slimy, gasping astronauts under a withering sun.

In the ages since, the tropical inland sea drained away, the continents merged and rifted, and the seafloor turned to stone. As fish conquered the land at last, the ocean was buried and forgotten. …

The dramatic change roughly marks the Taghanic Event—a mass extinction that razed corals, brachiopods, and squid-like creatures stuffed in elegant shells all over the world. It was one of almost twenty global mass extinctions in the history of complex life, a list that includes five cataclysmic outliers, when the planet nearly died, and one that might someday include us. …

The great Devonian mass extinction remains something of a mystery. There were oxygen-starved oceans, fueled by an explosion of massive algae blooms—perhaps even driven by runoff from the land, as the emerging world of trees carried out their massive geoengineering project, greening the continents. Other research adds invasive species spread by surging seas, preposterous volcanoes and extreme climate change to the chaos for good measure. Whatever form this destroyer took, it laid waste to 99.99 per cent of the largest reef systems the world has ever known—the so-called “megareefs” of the Devonian, ten times more extensive than our own. Trilobites, tentacled drifters, fish wrapped in heavy armor—nothing was spared.

RTWT

I still have somewhere boxes full of unprocessed limestone rocks full of Devonian brachiopods I collected back when I was in high school.

19 Feb 2013

Too Late For Valentine’s Day, Alas!

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Devonian Comura trilobite from Hamar Laghdad Formation, Erfoud, Morocco

The advertising description reads:

This INVESTMENT GRADE spiny Comura trilobite represents the finest possible quality of preservation, completeness and displays an entire array of authentic spines freed completely from their matrix and exposed. This species is one of the most complex and difficult to prepare in this manner and such a project encompasses untold hours of meticulous preparation and skill. All three rows of spines running down the lobes of this trilobite and all other cephalonic spines have been exposed and are 100% AUTHENTIC. The trilobite is prepared with the head (cephalon) protruding up off of the rock and rock is removed from beneath. This time-consuming fantastic, natural position gives the impression as if it is attempting to crawl off its original limestone matrix. Examples like this come along only on very rare occasion and 100% authentic examples are becoming increasingly difficult to find. Perfect for the most demanding advanced collector striving to acquire specimens based on the finest rarity and quality.

I didn’t actually realize that trilobites came in investment grade, and I bet they didn’t either, but I will gladly concede that is is one heck of a nice trilobite.

The photos don’t really make it clear that this bad boy is only 2.4″ long, and the whole shooting match, rock and all, is less than 3 1/2″ long. Nonetheless, they are asking $4250.

Hat tip to Fred Lapides.


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